She gained a BA in English Literature from Exeter University, after which she received a scholarship to the University of Kansas, later returning to Exeter where she gained a Ph.D. in English and Women's Studies.

In 1986 Caroline Lucas joined the Green Party, inspired by the book Seeing Green by Jonathon Porritt.

Caroline Lucas described her first contact with the Green Party:

"I marched out of my bedsit and up and down Clapham High Road looking for what I fondly imagined would be the large offices of the Green Party. I couldn't find anything, but eventually came across a sort of broom cupboard behind a Chinese restaurant. I walked in, volunteered and, over time, became their first paid press officer."

As well as her roles for the Green Party, she had a stint at Oxfam when she won the Green Party's second County Council seat in 1993 and served on Oxfordshire County Council until 1997.

In June 1999 Caroline Lucas was elected to represent the South East of England region as one of the Green Party's first MEPs.

In 2008 she was elected Green Party leader.

On 6 May 2010, Caroline Lucas became the first Green Party MP in the UK parliament when she won Brighton Pavilion with a majority of 1,252 over Labour's Nancy Platts.

She stepped down as leader of the Green Party in 2012, however in 2016, she was elected joint leader of the Green Party along with Jonathan Bartley.